Question

what is the name of this hydrocarbon?
o 3 - isopentane
o 2 - methylbutane
o 3 - methylbutane
o 1,2 - methylpropane

Explanation:

1. First, find the longest carbon - chain. Here, the longest continuous carbon - chain has 4 carbon atoms, so the parent hydrocarbon is butane.
2. Then, identify the position of the methyl group. The methyl group ($-CH_3$) is attached to the second carbon atom of the butane chain. According to IUPAC naming rules for branched - chain alkanes, the name is 2 - methylbutane.

Answer:

B. 2 - methylbutane